1. Field of the Invention
The present invention relates to a card type peripheral apparatus and a host apparatus.
2. Description of the Related Art
There exist PC cards serving as various card type peripheral apparatuses which, when put to use, are attached to a host apparatus such as a personal computer. Known PC cards include the PCI Card that communicates via a PCI bus and the PCI ExpressCard that communicates over a PCI Express bus permitting higher data transfer rates than the PCI bus (see Japanese Patent Laid-open Nos. 2005-275909 and 2006-155183).
Illustratively, the PCI ExpressCard is standardized physically, electrically and logically. While complying with this standard, the PCI ExpressCard is subject to diverse device-specific control protocols that vary from one manufacturer to another.
The ExpressCard standard stipulates not only the shape and dimensions of the card but also the specifications of the slot and connectors of the host apparatus. For that reason, any ExpressCard complying with the ExpressCard standard can be physically connected to the host apparatus.
The PCI Express interface subsumed under the ExpressCard standard is also standardized electrically and logically. Thus any ExpressCard complying with the PCI Express standard can also be connected to the host apparatus electrically and logically.
On the other hand, the control protocols by which the host apparatus communicates with the cards have yet to be standardized. The control protocol specifications vary from one manufacturer to another and even from one device to another.
In the past, the host apparatus typically used a given combination of a vendor ID, a device ID, a revision ID, a subsystem ID, a subsystem vendor ID, and a class code as discriminating factors by which to identify only those cards that comply with a particular control protocol among diverse control protocols. Where different manufacturers using different devices fabricated cards subject to the same control protocol, connectivity (i.e., normal communication) between these cards on the one hand and the host apparatus on the other hand was guaranteed by having the host apparatus additionally furnished with information about the new card manufacturers and their devices being used.
The connectivity above has generally been ensured in the above-outlined manner by personal computer (PC) systems. Typically, a device driver corresponding to any newly introduced card is added to or updated in the host apparatus (i.e. PC system) over a network or using a suitable storage medium. The added or updated device driver supplies information about the new card manufacturer and their device to the host apparatus as additional discriminating factors.
There exist host apparatuses (electronic apparatuses) such as card-attachable cameras so designed as to be incapable of receiving, over a network or using a storage medium, device drivers corresponding to any newly introduced cards. This type of host apparatus may identify given cards in the same manner as PC systems. In that case, the host apparatus may identify and communicate with a first card subject to a given control protocol but may not communicate with a second card fabricated by a different manufacturer using a different device despite the fact that the second card complies with the same control protocol and is connectable physically, electrically and logically to the host apparatus.
The problem above is encountered by the host apparatus being incapable of discriminating the second card as one that can be controlled under the control protocol specific to the host apparatus in question. Since it is impossible to add or update device drivers in the host apparatus over a network or using a storage medium in order to reflect the information about the new card manufacturer and the new device, the host apparatus may have to be brought to its manufacturer or a service center for device driver update. This can be a serious problem contingent on the urgency of the user's need to use the electronic apparatus.